Multislice computed tomographic measurements of optic nerve sheath diameter in brain injury patients.

BACKGROUND: Currently, the measurement of optic nerve sheath diameter (ONSD) has been offered as a possible indicator of intracranial pressure (ICP). Increased ICP is observed during intracranial injury. The objective of this study was to evaluate the relationship between increased ONSD and positive intracranial findings from multislice computed tomography (CT) of the brain.

METHODS: In total, CT scans of 161 patients were retrospectively reviewed. The image that showed the largest ONSD was magnified five times.

RESULTS: The CT scan revealed intracranial lesions in 54 patients and no intracranial lesions in 107 patients. A significant relationship was observed between positive CT findings and increased ONSD: 5.60±0.75 mm vs. 5.35±0.75 mm (p=0.038). The area under the receiver operating characteristic curve was 0.600 (95% confidence interval, 0.508-0.692; p<0.039). A cut-off value of ≥5.0 mm had a sensitivity and specificity of 80% and 36%, respectively.

CONCLUSION: This study demonstrated a significant yet poor relationship between intracranial injury and increased ONSD from the multislice CT scan. Severe structural changes in the brain and trauma that causes bleeding have only limited effects on the extension of the optic nerve.